We currently have an AIX 5 ML6, TSM 5.2.6 server backing up most of our
clients.

We also have an IBM z/OS mainframe, V1R4 which has been independently
backing itself up using (i believe) dfshsm straight to some ancient
3490E drives.  We're running into problems fast with this backup
scenario, and this is the first time i've caught wind of this.

So, my question is that I see that TSM documentation for Unix clients
5.2.2 has this page:

http://publib.boulder.ibm.com/tividd/td/TSMC/GC32-0789-04/en_US/HTML/ans5000031.htm#oece

Therefore, I conclude that IBM does have a z/OS binary out there that
can connect to our AIX TSM server.  Can anybody verify this, please?
Our mainframe people are checking on this now, but I have a feeling I'd
get a quicker answer from this list.

Is there a specific avenue that we have to navigate through in order to
license this client?

Is there any other strategy to backup our z/OS server without having to
buy expensive hardware just to back it up?  According to our reseller,
we'd have to expand our 3584 library with 3590 drives just to backup the
mainframe.  But we'd really like to just add more LTO-based drives, and
the easiest way to do that would be with mainframe connectivity to our
existing TSM server.  Is there any reason why we can't or shouldn't go
this route?

Thanks for your help

Sergio